package interview;

public class interview_01_01 {
    public boolean isUnique(String astr) {
        int[] num=new int[26];
        for(int i=0;i<astr.length();++i){
            if(num[astr.charAt(i)-'a']==1) return false;
            num[astr.charAt(i)-'a']++;
        }
        return true;
    }
}
